Yes, cannabis can help with a lot of different types of nerve pain. It is good to be aware of where the pain originates because you can potentially start with a non-psychoactive option like a topical balm that cannot get you 'high.'
From there, you have great options like high ratio CBD capsules or tinctures (between 12:1-20:1 CBD:THC) that can relieve the inflammation cause by the nerve as well as helping with muscular pain in the back and legs as a result of the sciatica. Always start with small doses until you find your minimum effective dose.
I hope this helps!